A substantial disadvantage of these known plug-in connectors and the mode of connection thereof is to be seen in that the spring element impacts on a front rim of the retaining sleeve and then attempts to push it backwards. On the one hand, thereby, the front rim of the retaining sleeve is worn and optionally also bent outwards and damaged. On the other hand, undesired radial forces occur on the retaining sleeve by this front-side impact by the outwardly bent spring elements upon pushing back the retaining sleeve. Moreover, the returning or pushing back of the retaining sleeve by the spring element impacted on the front side also is only partly suitable and precise. Outward slipping off of the spring element on the front end of the retaining sleeve also cannot be excluded such that the spring element can also be bent and damaged. Moreover, the front end of the spring element is solidly and thus inflexibly formed.
From U.S. 2004/0106320 A1, a plug in connector is known, in which two plug parts can be connected to each other. A retaining sleeve is disposed in axially displaceable manner by a spring on a first plug part. On the second plug part, a spring element is disposed, which displaces the retaining sleeve backwards upon connecting the plug parts and snaps into a recess after reaching a specific displacement distance, such that the retaining sleeve is again automatically pressed forwards.
Moreover, from DE 33 37 686 C1, there is also known a plug in connector with two connectable plug parts, wherein a retaining sleeve is retained on a plug part biased via springs.